en_tn/act/21/37.md

as Paul was about to be brought

"as the soldiers were about to bring Paul" (See: rc://en/ta/man/translate/figs-activepassive) or "When the soldiers were ready to bring Paul"

the fortress

see how you translated this in verse Acts 21:34.

the chief captain

a military officer of about 600 soldiers

"Do you speak Greek? Are you not then the Egyptian, who previously led a rebellion and took the four thousand terrorists into the wilderness?"

The chief captain uses these questions to express his surprise. Paul is not who he thought he was. (See: rc://en/ta/man/translate/figs-rquestion)

Are you not then the Egyptian

Shortly before Paul's visit, an unnamed man from Egypt had launched a revolt against Rome in Jerusalem. Later he escaped "into the desert", and the commander wonders if Paul might be the same man.

the four thousand terrorists

"the 4000 men who kill and harm others who disagree with them" (See: rc://en/ta/man/translate/translate-numbers)